Electromagnetic devices, such as inductors and electrical transformers, may be constructed in many different ways. One common way is to have windings at least partially surrounded by a core, which may be, for example, made from a ferrite material. The core may be made from two or more pieces bonded to each other with an adhesive material such as an epoxy. The windings and core may be covered with a potting material and surrounded by a housing that allows the transformer to be mounted to another structure, such as a base plate or mounting pad.
Increasingly, electromagnetic devices are used in electronic devices wherein, for example, a transformer, including a transformer housing, may be placed within a larger enclosure. This can create problems for heat dissipation, for example, because of a lack of convective airflow over the transformer within the enclosure. Although there may be some heat transfer between the transformer and the base plate or mounting pad, this can actually cause additional problems.
Specifically, when one portion of the core dissipates much of its heat to the base plate, while the other portion of the core does not, a thermal gradient can be created between different portions of the transformer core. When different portions of the transformer core are at markedly different temperatures, the temperature gradient between the portions of the core can create thermally induced stress, which may then cause the core to crack or otherwise fail. Therefore, a need exists for a transformer arrangement configured to effectively dissipate heat so as to inhibit the formation of thermal gradients within the transformer, even when the transformer is disposed within a larger enclosure conducive to heat buildup.